In-situ zonal isolation for sand controlled wells

ABSTRACT

A process for sealing off one or more segments of a gravel packed well to reduce the production of undesirable fluids. The process includes the installation of a removable plug and the installation of a removable sealant at a location in the gravel packing to separate portions of the formation that produce desirable products from portions that produce less desirable products. A flow poison is then squeezed into the portion of the formation that produces less desirable products. With wireline or other low-cost wellbore workover systems, access is re-engaged with the preferred formation including removal of plugs and sealants without mechanical drilling. The process allows increased production of preferred fluids by preventing less or non preferred fluids from displacing the preferred fluids and also reduces lifting costs that would otherwise be expended for lifting and expenses related to separating and disposing of non preferred fluids.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional application which claims benefitunder 35 USC §119(e) to U.S. Provisional Application Ser. No.61/148,747, filed Jan. 30, 2009, entitled “In-Situ Zonal Isolation ForSand Controlled Wells,” which is incorporated herein in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

None.

FIELD OF THE INVENTION

This invention relates to producing fluids from a gravel packed well.

BACKGROUND OF THE INVENTION

In oil wells, it is common for sand or other solid gritty materials tobe carried from the producing formation along with the oil into thewellbore. Sand or other grit causes problems and wear for the productionequipment and preventing the introduction of such solids into thewellbore is very much desired. A common solution to prevent theproduction of such sand and grit is called “gravel-packing” the well.Gravel packing is basically the installation or packing of coarse sandor gravel material into the annular space between the productiontubing/liner and the casing or the formation in an open-hole productionarrangement. This gravel packed space extends along the outside of theproduction tubing/liner, may be the length of hundreds of pipe sectionsor joints. While most of the production tubing is impervious to liquid,the sections or joints adjacent the production zone are provided withslots or other pre-perforated openings in the peripheral wall. Thesejoints allow the produced liquids to pass from the outside of theproduction tubing into the interior of the production tubing. Theseslotted or pre-perforated joints are often screened and/or pre-packedwith sand control media and known to those skilled in the art as sandcontrol screens. The interior of the production tubing is where a pumpmay be disposed to carry or drive the liquids to the surface. Those thatare skilled in the art understand that there are a lot of differentproduction methods including free flowing and plunger lift as well asseveral variations of artificial lift such as gas lift, rod pumps,rotary PC pumps, jet pumps, electric submersible pumps and there areother less common methods of production methods.

The slotted or pre-perforated joints are commonly referred to as basepipe and typically includes holes or openings with a wire mesh, screen,or pre-packed sand control media around the outside to prevent the sandor gravel from leaking into the production tubing. There are othergravel packing arrangements where the base pipe has many small slitsthat are sized to prevent the passage of sand, but the function issubstantially the same. Gravel packing essentially forms a filterbarrier for the fine formation sand or grit, but allow the liquids topass freely through the interstices into the production tubing and becarried to the surface. However, the sand or gravel does notdiscriminate between different fluids and there are times whenundesirable fluids enter the gravel packing. For example, as a well isproduced, water, especially salt water, often encroaches into thehydrocarbon production zone as hydrocarbons are extracted. Typically,hydrocarbons and water are found together underground with water belowoil. As the hydrocarbons are withdrawn, the hydrocarbon/water interfacerises and it is not uncommon for water to begin to comprise asignificant portion of the total fluids produced. However, water canenter virtually anywhere in the completion in the well depending on thegeological conditions. Water may enter the mid to upper sections of aproducing zone when the upper sections have higher permeability and whenthe permeability ratios (vertical vs. horizontal) or natural formationfractures favor a situation where water may over-run the tighterproducing zones and show up first in mid to upper areas of thecompletion.

While the hydrocarbon/water interface may initially be confined to asingle production zone, it is also not uncommon for an oil well to bedrilled such that several oil bearing zones are accessed by the singlewell. Each of the hydrocarbon bearing zones may be isolated from oneanother by impermeable rock formations and each may have andhydrocarbon/water interface. The gravel packing may be exposed toseveral of these formations and fluids from one may translate along thegravel packing media to enter the production tubing at a differentlocation. This can be a concern as allowing different isolated zones tocommunicate with one another may create undesirable problems in that onezone may contaminate another. The separate zones may extend for miles socross contamination may have broad consequences.

There have been several efforts to stop the production of water ingravel packed wells. Typically, the formation pressure that drives thehydrocarbons toward the low pressure well comes from salt water that isdenser than hydrocarbons and, therefore, below the hydrocarbons. Assuch, the efforts have been focused on closing the gravel packed bedfrom the water at the bottom of the production zone. What hasn't beendeveloped is a suitable and effective technique to seal the well fromundesirable fluids that are above or in the middle of the target zonewhile permitting continues production from the target zone.

BRIEF SUMMARY OF THE DISCLOSURE

The invention generally includes a process for isolating and treating afirst fluid producing zone of an underground formation in an earthenwell where the well includes a second fluid producing zone further intothe ground than the first zone and a sand or gravel filter elementwithin an annular production space between a tubular production pipe andthe underground formation or casing pipe where access from the surfacethrough the production pipe to the second fluid producing zone ispreserved for subsequent production following the isolating and treatingprocedure. The process more particularly includes installing a wirelineor coiled tubing removable plug into the tubular production pipe at alevel further into the ground than the first fluid producing zone. Asettable, low viscosity permeability poison is injected into the tubularproduction pipe above the plug and out into the sand or gravel elementin the annular production space outside of the tubular production pipeand extending laterally to the casing pipe or formation to fill alongitudinal segment of the sand or gravel element in the annularproduction space between the first and second fluid producing zones toeventually separate and substantially seal the first and second zonesfrom one another against fluid flow in the sand or gravel element in theannular production space. The low viscosity permeability poison isconverted into a fluid seal forming a longitudinal barrier against flowwithin the sand control screen in the annular production space and atreatment is injected into the tubular production pipe onto the fluidseal and laterally through the annular production space and into theformation at the first fluid producing zone. The interior of the tubularproduction pipe is then opened up to regain access to the second fluidproducing zone by removing portions of the treatment material, the fluidseal and the isolation material within the tubular production pipe sothat fluids may enter the production pipe from the second zone and beextracted to the surface past the now treated first fluid producingzone.

A variation of the present invention is a process for isolating andtreating first and second fluid producing zones of an undergroundformation in an earthen well that includes a third fluid producing zonegenerally intermediate of the first and second zones where the secondzone is most distant from the surface and the first zone is closest tothe surface and the well also includes a sand or gravel filter elementwith an annular production space between a tubular production pipe andthe underground formation or casing pipe where access from the surfacethrough the production pipe to the third zone is preserved forsubsequent production following the isolating and treating procedures ofthe first and second zones. This variation includes installing awireline or coiled tubing removable plug into the tubular productionpipe at a level further into the ground than the second fluid producingzone and injecting a treatment into the tubular production pipe which issealed by at least the plug and laterally through the annular productionspace and into the formation at the second fluid producing zone. A layerof isolation material is deposited into the tubular production pipeabove the plug to form a first low permeability layer therein where attop of the layer is at a level below the first fluid producing zone. Afirst settable, low viscosity permeability poison is injected onto theisolation material in the production pipe and out into the sand orgravel element in the annular production space outside of the tubularproduction pipe and extending laterally to the casing pipe or formationto fill a longitudinal segment of the sand or gravel element in theannular production space between the first and second fluid producingzones to eventually separate and substantially seal the first and secondzones from one another against fluid flow in the sand or gravel elementin the annular production space. The low viscosity permeability poisonis then converted into a fluid seal forming a longitudinal barrieragainst flow within the sand control screen in the annular productionspace. A treatment may then be injected into the tubular production pipeonto the fluid seal and laterally through the annular production spaceand into the formation at the first fluid producing zone and then theinterior of the tubular production pipe is opened up to regain access toat least the third fluid producing zone by removing portions of thetreatment material, the fluid seal and the isolation material within thetubular production pipe so that fluids may enter the production pipefrom the third fluid producing zone and be extracted to the surface pastthe now treated first fluid producing zone.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention and benefitsthereof may be acquired by referring to the follow description taken inconjunction with the accompanying drawings in which:

FIG. 1 is a vertical and fragmentary cross sectional view of a not toscale prior art production system in a borehole;

FIG. 2 is a top and fragmentary cross sectional view of a not to scaleprior art production system in a borehole;

FIG. 3 is a vertical and fragmentary cross sectional view of a not toscale production system in a borehole showing the first steps in aprocess to isolate a non-preferred upper zone in the well

FIG. 4 is a vertical and fragmentary cross sectional view of a not toscale production system in a borehole showing the completed process forisolating a non-preferred upper zone in the well where the preferredzone is below the isolated zone;

FIG. 5 is a vertical and fragmentary cross sectional view of a not toscale production system in a borehole showing the first steps in aprocess to isolate a non-preferred upper zone and a non-preferred lowerzone in the well; and

FIG. 6 is a vertical and fragmentary cross sectional view of a not toscale production system in a borehole showing the completed process forisolating two non-preferred zones where the preferred zone is below atleast one of the isolated zones.

DETAILED DESCRIPTION

Turning now to the detailed description of the preferred arrangement orarrangements of the present invention, it should be understood that theinventive features and concepts may be manifested in other arrangementsand that the scope of the invention is not limited to the embodimentsdescribed or illustrated. The scope of the invention is intended only tobe limited by the scope of the claims that follow.

Turning to FIG. 1, a wellbore 10 is shown to be formed deep into theearth 11. Within the earth 11 are layers of various materials. Some ofthe layers are porous and permeable and permit fluids such as oil andwater and natural gas to transit through the pores and interstitialvoids. These layers are sometimes described as reservoir rock as the oilor hydrocarbons tend to move through permeable formations. Other layersin the earth are either without pores or have closed pores and do notpermit fluids to easily pass through. These layers tend to seal onepermeable layer from another and certain geological structures maycapture and hold oil and other hydrocarbons in areas called “traps”.Those deciding where to drill tend to target these hydrocarbon traps andproduce oil where it is found in quantities that justify the investmentto produce it.

In FIG. 1, a wellbore is generally indicated by the numeral 10 and isshown to have encountered three permeable zones, labeled A, B and C.Between zones A and B is shown an impermeable or substantiallyimpermeable layer 12. Between zones B and C is shown an impermeable orsubstantially impermeable layer 13. The wellbore 10 was drilled with adiameter large enough to accommodate casing pipe 15. As is well known inthe oil business, casing pipe 15 is inserted into position in thewellbore 10 and sealed to the earth 11 and to all the various zones andlayers that the wellbore 10 intersects by cement or other grout materialthat forms a layer 18 around the outside of the casing pipe 15. Thewellbore 15 is also shown to have been perforated by known perforatingtechniques that typically include shaped charges detonated to form anumber of openings through the casing pipe 15 and through the cementlayer 18 and also into the earth and into the various layers and zonestherein. In the present illustration, the perforations are illustratedas conical shaped perforations 19 with the pointed ends extending intothe earth in each of the permeable zones A, B and C. In actuality,perforations take various indescribable shapes with many fractures andfissures to allow and encourage fluids to drain from the formation intothe wellbore 10. With the perforations 19 extending through the wall ofthe casing pipe 15 and all the way into the formations of the earth 11,oil and other fluids in the permeable zones A, B and C are able to movethrough from the permeable zones and into the wellbore 10 until thepressure of the fluid inside the wellbore equalizes with the pressure inthe various permeable zones A, B and C.

While there are situations where the formation pressure is sufficient todrive hydrocarbons to the surface, it is more typical for fluids in thewellbore 10 to be extracted through a production assembly that includesany of various forms of artificial lift including down hole pumps. Theproduction assembly is generally indicated by the numeral 20 and thepump or other form of artificial lift is not shown. While conventionalproduction systems can include a substantial number of elements andprovide substantial capability at the bottom of a wellbore, theproduction assembly 20 is simplified to provide an explanation of theinvention and the problems that the invention is intended to overcome.The simplified production assembly 20 includes a production pipe 21having sand control screen base pipe 25 arranged to be in the vicinityof the producing zones of the wellbore 10. The production pipe 21 andsand control screen base pipe 25 are connected end to end with an upperpacker 22 and a lower packer 23 arranged to seal an annular productionspace 26 within the interior of the casing pipe 15 and around the sandcontrol screen base pipe 25 possibly including part of the productionpipe 21. It should be noted that sand control base pipe is little morespecialized than tubing in that sand control base pipe may includewrapping screens, sand, resin coated sand, sintered metal or otherfilter materials. A typical sand control screen's base pipe isperforated or slotted through the majority of the length of the pipejoint. While it is not clear from the drawings, a joint is typicallythirty feet or so in length and the perforations and slots may extendthe entire length but for several inches from each end so as not tointerfere with the collars where the joints are connected. Filter mediais applied over the pre-perforated or slotted base pipe and the ends ofeach joint of base pipe may be indistinguishable from regular tubingjoints. In FIG. 1, the sand control base pipe 25 has apertures, holes,perforations, slots or similar to allow fluids to pass from the outsideto the inside while the production pipe 21 has an impervious wall. Thepackers 22 and 23 are arranged so that all of the openings in the sandcontrol base pipe 25 and all of the perforations 19 are open to theproduction space 26 defined between the packers 22 and 23 and noopenings in the sand control base pipe 25 nor any perforations 19 areoutside of the production space 26.

It should be noted that while the well 10 in the illustrated example isprovided with casing pipe 15, the invention is also applicable foropen-hole production systems where the production space 26 extends fromthe production pipe 21 to the formation or to the inner wall of thewellbore 10. Open-hole production is well known and generally much lessexpensive than cased production. However, for simplicity in theexplanation, the invention is described with casing pipe 15 with theexpectation that those skilled in the art will readily understand thatthe inside of the casing pipe 15 is a substitute for the inner wall ofthe wellbore 10 and that without the casing pipe 15, the invention couldbe directly undertaken with the production space 26 extending fully tothe inner wall of the wellbore 10.

The sand control base pipe 25 as illustrated includes three productionsections 30 which are best explained in conjunction with FIG. 2. Turningto FIG. 2, base pipe 25 includes a large number of openings 31 to allowfluids to pass from the production space 26 into the interior 36 of thebase pipe 25. Around the outside of the base pipe 25 are a number ofspacers 32 which are generally welded to the exterior of the base pipe25. Surrounding the base pipe 25 and spaced from the periphery thereofis a wire wrapped screen 34. In other configurations, it should be noteddo not include spacers and a space 35 around the sand control base pipe25, but the invention will still generally work the same. The wirewrapped screen 34 creates a large number of small channels through whichoil or other fluids may transit from the production space 26 on a pathtoward the interior 36 of the sand control base pipe 25. Between thecasing pipe 15 and the wire wrapped screen 34 is the production space 26that is typically packed with sand or gravel. It is preferred that thesand and gravel also fill the perforation tunnels 19 and the space 35.It should be noted that in certain circumstances, it is very difficultand expensive to fully pack the space around the wire wrapped screen. Inthese circumstances the formation is allowed to collapse around thoseportions of the screen over time relying on the screen to keep the sandand grit out of the production tubing. While this is not optimal becausethe particle sizes against the wire wrapped screen are preferably of acommon and selected size to provide maximum porosity while filtering thesand and grit, oil may still be profitably produced and the inventionmay still be used in this circumstance to isolate portions of the wellfrom other portions. The production space 26 when packed with sand orgravel is sometimes called “gravel packing” or a “packed bed”. The meshsize of the wire wrapped screen 34 is determined in conjunction with themesh size of the sand or gravel so that the sand or gravel will not passthrough the wire wrapped screen 34, but oil and other fluids may. Thegravel or sand basically forms a filter cake that effectively filtersany sand or other grit that may be carried by the produced fluids to theperforations 19. The fluids continue to travel toward the interior 36 ofthe base pipe 25, but the formation sand and grit is held back by thesand or gravel in the production space 26.

The process of installing the casing pipe 15, the production assembly 20including the gravel bed in the production space is all well known. Itis only illustrated to set forth what may be accomplished by the presentinvention. And the primary concern that the present invention addressesis the circumstance when one or more of the production zones A, B or Cbegins to deliver amounts of undesirable fluids that justify investmentsinto the well to reduce the production of such undesirable fluids.Typically, when an oil or gas well produces a large percentage of water,the costs of lifting, separating and disposing of the produced water canjustify the costs of re-working a well to reduce the percentage ofproduced water at the bottom of the wellbore 10. By the presentinvention any portion of the earth formation may be isolated from theproduction assembly 20 whether the preferred production zone is above,below or between un-preferred production zones. Water production ineither oil or gas wells negatively impacts the production rate of thepreferred hydrocarbons. Water can take up a large percentage of the flowpath reducing the amount of hydrocarbons produced in a given amount oftime, and increasing frictional pressure drop and increasing density ofthe produced fluids thereby reducing the amount of production due toreduced pressure drop at the formation face. It should also be notedthat isolating portions of wells is not limited to hydrocarbonproduction. In wells that are drilled for fresh water, it is possible tohave salt water or contaminated fluid in adjacent formations that can beisolated from the desired zone by the present invention.

To most clearly explain the invention, the illustrated wellbore 10 willbe sealed off from zone A and will continue to produce only zones B andC after zone A has been fully closed off from the production assembly20. This would be appropriate if zone A had suffered a waterbreakthrough where very little hydrocarbons could be extracted. At thesame time, the production from zones B and C would need to be deemedsufficiently profitable to continue producing from those zones throughwellbore 10. Issues of profitability for zones B and C include currentand projected prices for hydrocarbons, the quality of the hydrocarbons,the contaminants that may make the hydrocarbons less valuable, theremaining water cut or percentage of water in the hydrocarbons, thedepth of the well and the cost of isolating zone A, the cost oftransporting the produced fluids to market and perhaps a dozen otherissues. Regardless, human judgment would dictate which wells and whichzones would have the inventive procedure implemented thereon.

Turning to FIG. 3, the process of isolating zone A would begin byinstalling a removable plug 41. Preferably, removable plug 41 maycomprise a material that can be washed away with a chemical treatmentsuch as an acid wash. Alternatively, a plug that may be retrieved with awireline device is suitable or the plug may be drilled/milled out. Theplug 41 is positioned below the zone to be isolated. In FIG. 3, the plug41 is shown to be below the impermeable layer 12 and therefore belowzone A. A layer 42 of isolation material such as fine grain sand, groundcalcium carbonate, salt, or other materials including even dense fluids,is then deposited upon the plug 41. The layer 42 of isolation materialforms a very low permeability or density balanced barrier to preventmaterials that are delivered into the wellbore subsequent to theinstallation of layer 42 from binding to the plug and complicating thesubsequent removal of the plug. The isolation material may be washed outlater by circulating fluid or jetting fluid to allow access to the plugas will be discussed later.

A low viscosity permeability poison is injected into the productiontubing 21 and delivered onto the layer 42 so as to flow out of the basepipe 25 and into the annular production space 26 all the way to theinside of the casing pipe 15 to form a fluid seal 44. The fluid seal 44is preferably formed by materials that flow through the gravel packingand preferably seal against the interior of the casing pipe 15 and fillthe interstices of the sand or gravel. There are known materials thatare able to serve the purpose that with the addition of small amounts ofa setting compound, heat, or time will rapidly set from a low viscosityfluid to a very high viscosity or crystalline structure. Essentially,this poison converts permeable sand or gravel into impermeable sand orgravel. Preferred materials include sodium silicate or sodiummetasilicate which is a stable and low viscosity liquid in neutralsolutions, but in acidic or alkaline solutions converts to form a solidprecipitate or high viscosity fluid that that kills or poisons thepermeability of the gravel pack rendering it nearly impermeable to flowfluid. With fluid seal 44 set in place, the production space 26 is nowdivided. As such, the upper zone A is available for treatmentindependent of zone B. Some treatments, such as an acid wash orfracturing with additional proppant enhance fluid production. Forexample, asphalts build up in the formation and perforations slowingdown production. In other circumstances, it is desired to slow or stopfluid production. Such production stopping may include the applicationof substantial forces that may be applied after the fluid seal is fullyset.

A permanent barrier to prevent the flow of fluids in zone A fromentering production assembly 20 is shown in FIG. 3. Rather than directthe low viscosity materials of the fluid seal 44 into the formationaccessed by the perforations 19 into the earth at zone A, the fluid seal44 is arranged below the lowest perforations in zone A. With the fluidseal 44 in place and set to have a very high viscosity or crystallinefluid seal 44, the production blocker 45 may be squeezed at a very highpressure to overcome the inherent formation pressure within zone A anddrive the formation blocker 45 through the interstices of the gravelpacking and deep into the crevices and fractures within perforations 19.The production blocker may comprise a micro cement, a resin and may alsocomprise sodium silicate. Under the higher pressure that may be appliedwith fluid seal 44 in place, the production blocker 45 is able to morefully fill the production spaces including the perforations 19 even ifthe materials are the same. It should be noted that it is preferred thatthe space 35 includes the sand and permeability poison to isolate thezones so that fluids are not able to bypass the seal and passlongitudinally along the sand control base pipe 25 in space 35.

The next steps of process relate to opening up fluid communicationbetween the production pipe 21 and the sand control base pipe 25.Referring now to FIG. 4, the materials that form the production blocker45 are removed from inside the base pipe 25 preferably by irrigationwith a circulation of liquids. Chemical treatments such as by directinga stream of suitable acid or caustic through a coiled tubing string orother work string where the dissolved portions of the production blocker45 and fluid seal 44 are washed up to the surface through the annulus ofthe production pipe formed outside the coiled tubing string. It shouldbe noted that if water is a suitable material for removing the barrieror production blocker within the interior of the base pipe 25, waterwould be preferred over other more expensive and harsher chemicals.Moreover, these elements may also be drilled out. The coiled tubingstring or other work string is not shown, but rather the results of theremoval of the portions of the production blocker 45, the fluid seal 44,the isolation layer 42 and the plug 41 within the production pipe areremoved. At the same time, the perforations 19 in zone A are blockedfrom further production and the system for blocking does not allowfluids from zone A to bypass the fluid seal 44 and blocker 45 because ofthe cement 18, the permeable layer 12. Leaving the fluid seal 44 inplace provide extra confidence that fluids in zone A are not allowed tomove along a narrow interface of the blocker 45 and the lowestperforations 19 and then descend within the gravel pack to be then drawninto the base pipe 25 through a production section 30.

A similar procedure may be used to isolate zone A and C from zone Bwhere zone B is producing desirable fluids but zones A and C are in needof treatment to enhance production or to be shut off. Referring now toFIG. 5, a removable plug 51 is installed below the lowest perforation 19in zone C. A low permeability isolation layer or high density fluidlayer 52 may be installed on the plug 51 if there is further productionlower in the wellbore. However, in the situation where zone C is thelowest producing formation and it is producing water in a hydrocarbonwell, the need to protect the plug 51 with the low permeabilityisolation material is probably not necessary as the plug will unlikelyever be recovered. A treating string with a packer is positionedadjacent layer 13 and used to squeeze a treatment into zone C. In thedrawings, the zone C is desired to be closed to further production and aproduction blocker 55 is formed by the high pressure insertion ofmaterial that extrudes through the gravel packing, the wire wrappedscreen, the space between the wire wrapped screen and the periphery ofthe base pipe and preferably into the perforations 19 in zone C. Uponcomplete curing or reaction of the production blocker 55, the wellhole10 is completely isolated from any fluids in zone C. With the productionblocker inside the base pipe 25, and depending on the distance of theproduction blocker 55 from zone A, a second isolation layer 62 may beinstalled directly on the production blocker 55. With the isolationlayer 62 installed, a fluid seal 64 is installed as described previouslywith a production blocker 65 installed to seal zone A from the wellbore10. Again, with zone A sealed from zone B, zone A may alternatively besubjected to a treatment that enhances fluid production in zone A beforefluid communication is re-established with zone B. As described in thefirst embodiment, the production blocker 65 and fluid seal 64 within thebase pipe 25 are at least partially removed along with the isolationlayer 62 to allow access to the base pipe adjacent zone B as shown inFIG. 6. It should be noted that while it is preferred to open theinterior of the base pipe 25 using wireline tools or coiled tubing tominimize rig costs and other expenses, drilling out the productionblocker 65 within the base pipe 25 is certainly an option that may beused. Also, if no production is intended in zone C or below, theproduction blocker 55 is not removed from the inside of the base pipe25.

It should be noted that the process has been described to stopproduction in certain zones within the well, but in many othercircumstances, it is desirable to stimulate certain formations withoutsubjecting other zones to such stimulation. The technique forstimulating and isolated section begin by isolating the target zone fromthe non-target zone. Referring again to FIG. 3, if zone A were deemed tobe in need of treatment for which it is desirable not to subject zones Band C to the same treatment, a removable plug 41 would be inserted intothe base pipe 25 as described before. Layer 42 and fluid seal 44 wouldalso be installed as described before. However, rather than install theproduction blocker 45, a treatment such as fracturing materials andpressure may be applied or an acid treatment or various kinds of washingmay be performed. The inventive technique of the present inventionprovides for isolation of zone A without forgoing subsequent productionof zones B and C by removing the fluid seal within the base pipe 25after the treatment of zone A has been completed. Production would thenresume after removal of the fluid seal 44, the layer 42 and the plug 41as described before. As should be easily understood, the inventionprovides for isolating one zone from another and then being able toapply materials under pressure into isolated zones. The fluid seal 44that remains outside of the base pipe 25 essentially operates as apacker within the casing 15 or to the formation when packers were notoriginally included in the completion. Once in place with the base pipe25 opened to the desirable zones, production may be optimized.

In closing, it should be noted that the discussion of any reference isnot an admission that it is prior art to the present invention,especially any reference that may have a publication date after thepriority date of this application. At the same time, each and everyclaim below is hereby incorporated into this detailed description orspecification as additional embodiments of the present invention.

Although the systems and processes described herein have been describedin detail, it should be understood that various changes, substitutions,and alterations can be made without departing from the spirit and scopeof the invention as defined by the following claims. Those skilled inthe art may be able to study the preferred embodiments and identifyother ways to practice the invention that are not exactly as describedherein. It is the intent of the inventors that variations andequivalents of the invention are within the scope of the claims whilethe description, abstract and drawings are not to be used to limit thescope of the invention. The invention is specifically intended to be asbroad as the claims below and their equivalents.

REFERENCES

All of the references cited herein are expressly incorporated byreference. The discussion of any reference is not an admission that itis prior art to the present invention, especially any reference that mayhave a publication data after the priority date of this application.

The invention claimed is:
 1. A process for isolating and treating afirst fluid producing zone of an underground formation in an earthenwell where the well includes a second fluid producing zone further intothe ground than the first zone and a sand or gravel filter elementwithin an annular production space between a tubular production pipe andthe underground formation or casing pipe where access from the surfacethrough the production pipe to the second fluid producing zone ispreserved for subsequent production following the isolating and treatingprocedure, where the process for isolating the first zone comprises: a)installing a wireline or coiled tubing removable plug into the tubularproduction pipe at a level further into the ground than the first fluidproducing zone; b) injecting a settable, low viscosity permeabilitypoison into the production pipe and out into the sand or gravel elementin the annular production space outside of the tubular production pipeand extending laterally to the casing pipe or formation to fill alongitudinal segment of the sand or gravel element in the annularproduction space between the first and second fluid producing zones toeventually separate and substantially seal the first and second zonesfrom one another against fluid flow in the sand or gravel element in theannular production space; c) converting the low viscosity permeabilitypoison into a fluid seal forming a longitudinal barrier against flowwithin the sand control screen in the annular production space; d)injecting a treatment into the tubular production pipe onto the fluidseal and laterally through the annular production space and into theformation at the first fluid producing zone; and e) opening up theinterior of the tubular production pipe to regain access to the secondfluid producing zone by removing portions of a treatment material, thefluid seal and an isolation material within the tubular production pipeso that fluids may enter the production pipe from the second zone and beextracted to the surface past the now treated first fluid producingzone.
 2. The process for isolating a first fluid producing zone in anearthen well according to claim 1 wherein treatment includes one or morefluids to increase the fluid production in the first zone.
 3. Theprocess for isolating a first fluid producing zone in an earthen wellaccording to claim 1 wherein treatment includes one or more fluids toreduce fluid production in the first zone.
 4. The process for isolatinga first fluid producing zone in an earthen well according to claim 1wherein treatment includes one or more fluids to stop fluid productionin the first zone.
 5. The process for isolating a first fluid producingzone in an earthen well according to claim 1 wherein the step of openingup the interior of the tubular production pipe further includes removingthe removable plug.
 6. The process for isolating a first fluid producingzone in an earthen well according to claim 1 wherein the step of openingup the interior of the tubular production pipe includes circulating afluid to wash a portion of at least one of the fluid seal and thetreatment from the tubular production pipe.
 7. The process for isolatinga first fluid producing zone in an earthen well according to claim 1wherein the step of opening up the interior of the tubular productionpipe includes drilling a portion of at least one of the fluid seal andthe treatment.
 8. The process for isolating a first fluid producing zonein an earthen well according to claim 1 wherein a production blocker isforced under elevated pressure into perforations formed into the earthenformation at a non-preferred zone.
 9. The process for isolating a firstfluid producing zone in an earthen well according to claim 1 wherein thepermeability poison comprises sodium silicate.
 10. The process forisolating a first fluid producing zone in an earthen well according toclaim 1 wherein the treatment comprises sodium silicate to block furtherproduction in the first zone.
 11. The process for isolating a firstfluid producing zone in an earthen well according to claim 1 furtherincluding the step of depositing a layer of isolation material in thetubular production pipe and onto the plug to form a low permeabilitylayer therein where a top of the layer is at a level generally betweenthe first and second fluid producing zones before injecting thepermeability poison.
 12. A process for isolating and treating first andsecond fluid producing zones of an underground formation in an earthenwell that includes a third fluid producing zone generally intermediateof the first and second zones where the second zone is most distant fromthe surface and the first zone is closest to the surface and the wellalso includes a sand or gravel filter element with an annular productionspace between a tubular production pipe and the underground formation orcasing pipe where access from the surface through the production pipe tothe third zone is preserved for subsequent production following theisolating and treating procedures of the first and second zones, wherethe process for isolating the first and third zones comprises: a)installing a wireline or coiled tubing removable plug into the tubularproduction pipe at a level further into the ground than the second fluidproducing zone; b) injecting a treatment material into the tubularproduction pipe which is sealed by at least the plug and laterallythrough the annular production space and into the formation at thesecond fluid producing zone; c) depositing a layer of isolation materialinto the tubular production pipe above the plug to form a first lowpermeability layer therein where at top of the layer is at a level belowthe first fluid producing zone; d) injecting a first settable, lowviscosity permeability poison onto the isolation material in theproduction pipe and out into the sand or gravel element in the annularproduction space outside of the tubular production pipe and extendinglaterally to the casing pipe or formation to fill a longitudinal segmentof the sand or gravel element in the annular production space betweenthe first and second fluid producing zones to eventually separate andsubstantially seal the first and second zones from one another againstfluid flow in the sand or gravel element in the annular productionspace; e) converting the low viscosity permeability poison into a fluidseal forming a longitudinal barrier against flow within the sand controlscreen in the annular production space; f) injecting the treatmentmaterial into the tubular production pipe onto the fluid seal andlaterally through the annular production space and into the formation atthe first fluid producing zone; and g) opening up the interior of thetubular production pipe to regain access to at least the third fluidproducing zone by removing portions of the treatment material, the fluidseal and the isolation material within the tubular production pipe sothat fluids may enter the production pipe from the third fluid producingzone and be extracted to the surface past the now treated first fluidproducing zone.
 13. The process for isolating and treating first andsecond fluid producing zones of an underground formation in an earthenwell according to claim 12 wherein the treatment for the first zoneincludes one or more fluids to increase the fluid production in thefirst zone.
 14. The process for isolating and treating first and secondfluid producing zones of an underground formation in an earthen wellaccording to claim 13 wherein the treatment for the second zone includesone or more fluids to increase the fluid production in the second zone.15. The process for isolating and treating first and second fluidproducing zones of an underground formation in an earthen well accordingto claim 13 wherein the treatment for the second zone includes one ormore fluids to stop the fluid production in the second zone.
 16. Theprocess for isolating and treating first and second fluid producingzones of an underground formation in an earthen well according to claim12 wherein the treatment for the first zone includes one or more fluidsto stop the fluid production in the first zone.
 17. The process forisolating and treating first and second fluid producing zones of anunderground formation in an earthen well according to claim 16 whereinthe treatment for the second zone includes one or more fluids toincrease the fluid production in the second zone.
 18. The process forisolating and treating first and second fluid producing zones of anunderground formation in an earthen well according to claim 16 whereinthe treatment for the second zone includes one or more fluids to stopthe fluid production in the second zone.